And all those scientists roaming all over the place up there... wonder what's the albedo differential of yellow snow. (dotearth.blogs.nytimes.com)
One example that I wasn't previously aware of, were the climate events of 536 AD — «dry fogs», crop failures, «dim suns» and yellow snow etc. — features consistent with a large volcanic eruption, possibly near the site of Krakatoa — and which correlates with evidence of a sulphate peak in the North GRIP ice core at the same time. (realclimate.org)
This goes for rules too — think: «never eat yellow snow» or «never bluff a guy nick - named bruiser.» (askmen.com)